In such methods, the elastic bending of the turbine blade which is caused by cutting forces is a known problem. This bending detrimentally affects the accuracy of the machining and can lead to vibrations in the turbine blade, as a result of which the surface quality in the machined profile sections is impaired.
A solution of the above-mentioned problem is known from document EP-2618961-B1, in which the turbine blade during the machining is supported in certain sections by means of a back stay which can travel along the blade axis. This back stay has a number of plungers which can move along their axis and are pressed against the turbine blade in order to support this. This back stay requires a relatively large amount of space all around the turbine blade, requires additional drives, detrimentally affects the accessibility to the turbine blade and can obstruct the falling of chips. Moreover, during a change of the profile section which is to be machined the back stay has to be circumvented by the tool, which necessitates a considerable programming cost and involves a certain risk of collision anyway. Moreover, the finish-machined blade surface can be damaged by the plungers, for example by these leaving behind impressions.
Documents CH-693610-A5 and WO-2015/157166-A1 show devices with clamping jaws which are adapted to the blade profile, but the workpiece has to be reclamped there in order to be able to machine all the profile sections.
Starting from this prior art, an aspect of the invention is based on the object of proposing a method for cutting machining of turbine blades, in which the turbine blade is machined in a single chucking, wherein in the region of the blade tip the chucking is such that a bending of the turbine blade as a consequence of cutting forces is reduced and vibrations are damped.
This aspect is achieved by a first profile section which is adjacent to the blade tip being machined first of all by the tool, by the tool then being removed and the tool spindle grabbing an additional clamping device which has clamping jaws adapted to the first profile section, by the additional clamping device being positioned on the blade-tip clamping device in such a way that the clamping jaws rest in the first profile section, and by the tool spindle grabbing a tool and machining the remaining profile section with it.